10.3.5 Overflow

If the amount allocated from the previous mark and sweep operation is less than
:minimum-for-sweep, the GC does not perform a mark and sweep. Instead it allocates a small-objects buffer in the big-chunk area (the second segment in the first generation). The minimum and maximum sizes of this buffer are specified by
:minimum-overflow and
:maximum-overflow, which can be set by set-gc-parameters. If the GC fails to find a buffer of this size, it looks for a smaller buffer, and if that fails it enlarges the big-chunk area (and the process size) by the amount needed to allocate a buffer of the size of the currently allocated area in generation 0, up to a maximum amount specified by
:maximum-overflow
.